Numerical and Experimental Research on the Influence of Clearance Between Impeller and Cover on the Pump Performance

Centrifugal pump is widely used and plays an important role in national economy. However, according to plenty of engineering practice and model tests, it indicated that the clearance between the impeller and pump cover is an important parameter for leakage loss and hydraulic efficiency. In this paper, a single stage centrifugal pump was selected to study the influence of clearance between impeller and pump cover on the hydraulic performance through combination of experiment and numerical simulation. Commercial software ANSYS CFX was employed to simulate the internal flow field with a clearance of 0 mm, and the experimental verification was carried out. The results presented that only a small difference was generated between experiment and numerical simulation, the maximum error is less than 4%, which can ensure the accuracy of the numerical calculation. At the same time, by comparing the simulation results with clearance of 0.1 mm, 0.22 mm, 0.42 mm and 0.62 mm, it found that with the increase of clearance, the impact loss at the tongue was significantly improved. In addition, with the increase of clearance, the effect of water flowing out from clearance interferes with the water at impeller inlet gradually improve. Finally, the hydraulic experiment with different clearance were carried out to verify the numerical result. Therefore, this research results have significant guiding effect for the design of clearance between impeller and cover in the future.